Francisco Santos told campaigners for the men’s’ release and politicians that Colombia was a democracy with an independent judiciary.
Members of the Oireachtas Foreign Affairs Committee quizzed Mr Santos on the delay in the delivery of a verdict on three Irishmen accused of assisting left wing guerrillas in Colombia.
Mr Santos had earlier told a group of international observers that he has no control over when the presiding judge will deliver the verdict.
The vice president said there was no way politicians could pressurise the judge into saying when the verdict should be delivered.
The trial of the three, Martin McCauley, Niall Connolly and James Monaghan, ended eight months ago, two years after they were arrested after travelling to the FARC-controlled area of the country.
They are accused of travelling to Colombia on false documents and of training FARC guerrillas, particularly in the use of mortars. Supporters say they are innocent of the charges, that they are victims of a show trial and have accused senior Colombian government ministers of making prejudicial remarks about the three.
Sinn Féin Northern Assembly member Catríona Ruane, chair of the Bring Them Home campaign, claimed Mr Santos made prejudicial remarks about the case at the meeting with the international observers yesterday.
She also alleges that Mr Santos, at a meeting in January, categorically assured her and others that a verdict would be delivered by March, contradicting, according to Ms Ruane, yesterday’s argument of a gap between politicians and the judiciary.
Ms Ruane also accused the Taoiseach Bertie Ahern and the Government of not being vocal enough in defence of the rights of the three Irish citizens, who are being held in the tough La Mondelo jail in Colombia.
Around 100 people protesting against the continued incarceration of the three gathered outside Leinster House as Mr Santos met with the Foreign Affairs Committee. They said the three were innocent of the charges and should be allowed home immediately.
Among the protesters were Mr McCauley’s wife Christine and son Padraig, Niall Connolly’s brother Frank, the Sinn Féin TD Martin Ferris and the singer Christy Moore.
Mr Moore said he was attending as a friend of all three Irishmen.
Their continued imprisonment and trial was obviously an injustice, the singer said.